Flashback: Le Mans 2014 and the most efficient race car

This weekend, Audi will be battling for its 14th victory in the Le Mans 24 Hours. The aim, again, is to cover the longest distance with maximum efficiency because, since 2014, regulations have been in effect that require the teams to achieve the maximum from a specified amount of fuel. Audi was already the best in this discipline in the debut year.